Fig. 2. NMR titration of 1a with DIPEA and DBU. (A) 1H NMR spectra of 1a in the presence of 0, 0.5, 1, 2 and 5 equivalents of DIPEA. (B) 1H NMR spectra of 1a in the presence of 0, 0.5, 1, 2 and 5 equivalents of DBU. (C) 13C NMR spectra of 1a (bottom), 1a with 5 equivalents of DIPEA (middle) and 1a with 5 equivalents of DBU (top).
